1. Field of the Invention
The present invention relates to a communication mediation apparatus and communication method which implement communication extending over a plurality of wireless communication networks, and a computer readable medium.
2. Related Art
In recent years, wireless communication devices adopting Bluetooth (trademark, hereafter omitted) communication standards to implement data transmission and reception between communication devices by using frequencies in a 2.4 GHz band and the frequency hopping technique, have increased. By using the communication standards, the communication can be easily implemented between communication devices which are relatively at a short distance.
According to the Bluetooth standards, each network is called a piconet. If one of the devices in each piconet is designated as a master device, the number of devices (slave devices) that can be connected to the master device is limited to up to seven. If eight or more devices are to be connected, it must be made possible to recognize that devices connected to each piconet belong to another piconet as well. A group of piconets constituted with such an object is called a scatternet. It doesn't matter if the number of devices belonging to each of the piconets included in the scatternet is less than eight.
In the scatternet, a predetermined slave device which connects piconets to each other goes round a plurality of piconets in a time division manner, and thereby multiplex communication is implemented virtually. This operation is called piconet switching. A device belonging to each piconet communicates with a device belonging to another piconet via the device which goes round the piconets in the time division manner.
Outlines of mechanisms of the piconets and scatternet are disclosed in United States Patent Application No. 2004/0136338 (for example, FIG. 2).
If a certain device desires to communicate with a device belonging to another piconet at this time, the certain device is kept waiting until the predetermined slave device conducts piconet switching to the piconet to which the device desired to communicate with by the certain device belongs.
If a scatternet is constituted, communication among a plurality of piconets included in the scatternet is implemented using the piconet switching.
However, communication with the piconet to which the opposite party of the communication belongs is restricted to within time when the slave device is piconet-switched to the target piconet. If communication timing does not coincide with piconet switching timing in the scatternet, waiting for communication start occurs frequently. As a result, not only the throughput is lowered, but also there is a possibility that a problem will occur in service of video images and voices required to have the real time property.